1. Field of the Invention
The present invention relates to a fuel cell system. More particularly, the present invention relates to a fuel cell system including a reaction source supplier to provide hydrogen along with an oxidant.
2. Description of the Related Art
A fuel cell is a power generation system for producing electrical energy through the electrochemical redox reaction of oxygen and a fuel, such as hydrogen or a hydrocarbon-based material such as methanol, ethanol, natural gas, or the like.
A fuel cell can be classified into a phosphoric acid type, a molten carbonate type, a solid oxide type, a polymer electrolyte type, or an alkaline type depending upon the kind of electrolyte used. Although each of these different types of fuel cells operates in accordance with the same basic principles, they can differ from one another in the kind of fuel, the operating temperature, the catalyst, and the electrolyte used.
Recently, a Polymer Electrolyte Membrane Fuel Cell (PEMFC) has been developed. The PEMFC has power characteristics that are superior to those of conventional fuel cells, as well as a lower operating temperature and faster start and response characteristics. Because of this, the PEMFC can be applied to a wide range of applications, such as portable electrical power sources for automobiles, distributed power sources for houses and public buildings, and small electrical power sources for electronic devices.
A PEMFC is essentially composed of a stack, a reformer, a fuel tank, and a fuel pump. The stack forms a body of the PEMFC, and the fuel pump provides the fuel stored in the fuel tank to the reformer. The reformer reforms the fuel to generate the hydrogen gas and supplies the hydrogen gas to the stack. Accordingly, in the PEMFC, a fuel stored in the fuel tank is pumped to the reformer through a fuel pump and then the reformer reforms a fuel to generate a hydrogen gas. The hydrogen gas and air are supplied to a stack through respective pumps. The stack generates electrical energy through an electrochemical reaction of the hydrogen gas and oxygen in the air.
A fuel cell system in accordance with the conventional art contains pumps for respectively supplying a fuel stored in a fuel tank to a reformer and air to a stack. Since parasite powers are increased for driving such pumps, energy efficiency of the whole system is deteriorated. The prior fuel cell system also needs space for equipping such pumps and so it is difficult to make the whole system down-sized and compact.